Steering probes such as shown in U.S. Pat. No. 5,307,611 include a yoke or pendulum structure with an upper end pivotally mounted to a harvester for pivotal movement about a horizontal axis. A sensor at the pivotal mounting senses the rotational position of the yoke as lower ends of the yoke engage the opposite sides of the crop row. As the yoke pivots from a neutral position when the harvester becomes misaligned with the crop row, the sensor provides an error signal so the vehicle can be steered to compensate for the misalignment with the crop row. Such steering probes are commonly utilized with cotton harvesters to keep row units aligned with rows of cotton plants.
Because of the geometry and pivot location of conventional steering probes, they are not readily adaptable to narrow row harvesters. For example, in ultra-narrow row cotton, interference results between the pendulum structure and a row of cotton adjacent the row entering the row-receiving area of the unit. Rotation of the pendulum structure about the upper pivot as the row becomes misaligned with the unit is very limited, and the relatively small angular displacement of the pendulum results in a correspondingly small sensor signal which can lead to sensing inaccuracies, non-repeatability, and slow steering response.
Previously available steering probes are not readily adaptable to row units with variable row spacing such as shown in commonly assigned U.S. Pat. Nos. 6,550,230; 6,293,078 and 6,212,864. The variable row spacing units include a cutting device for directing a cut row of crop into a standing row, and mounting steering probes on either the cut or the standing side of the row units has been a continuing source of difficulty.
Large diameter stalks passing between the lower ends of a relatively rigid probe can result in further problems. Without adequate probe flexibility, plant movement between the ends is hampered, damage to crop can result from passage through the ends of the probe, and the assembly encounters added stress and wear. If the operator adjusts the probe end spacing to accommodate the largest plants without damage, probe sensitivity to row misalignment is compromised in areas of the row where smaller plants are encountered.